1. Field of the Invention
The invention relates to the field of devices for providing cutaneous-based markings in association with x-ray examination procedures. More particularly, the invention relates to a marker device to be used in podiatric evaluations, wherein the marker device encompasses and defines the area under visual examination in such a way that this area can later be correlated with a radio-photograph.
2. Description of the Prior Art
In the field of podiatric evaluations there is often times great difficulty in determining the type and location of a sub-cutaneous problem (under the skin). In particular, while naturally-occurring cutaneous landmarks, such as palpable masses and cutaneous lesions, indicate that there may be a deep structure problem in a foot, it is generally impossible to determine--in the absence of x-ray photographs--whether the problem is associated with a bone of the foot, and if it is, which bone is the source of the problem. Highlighting the area of interest with a marker that is easily seen on the radiograph focuses the podiatrist's attention and thus aids in determining the course of treatment. Failure to so mark the radiograph, or marking in such a way that even small portions of the area of interest are obscured may seriously hinder the diagnostic examination of the problem area. Inadequate diagnostic examination can then lead to improper and/or inadequate treatment.
Present methods of converting visual localization to x-ray localization vary, but generally all involve the use of a radiopaque material--such as barium sulfate or lead--to highlight the area of interest. Commonly, the radiopaque material is placed on (or in) the patient prior to the radiography; however, one technique involves placing the radiopaque material directly on the photographic medium which is to be exposed to the x-radiation. This technique relies on the coordination among the examining physician, the x-ray technician, and the radiologist. In many cases this coordination is not possible; in others the information provided is too general and the probability of improperly marking and evaluating the area of interest is heightened.
Another technique, described by Duska (U.S. Pat. No. 4,506,676), utilizes an adhesive tape with the radiopaque material incorporated into the tape, which tape is then applied to the patient's skin. As it is added to the tape, the radiopaque material is formed into a plurality of arrows or dots. The tape is then placed on the patient's body so that the image of the radiopaque symbols point to the area of interest on the x-ray film. A major shortcoming of the Duska technique is that it tape only extends up to, and does not surround, the area of interest. Its usefulness is thus limited to the evaluation of large bones, such as the bones of the legs and arms; in the examination of small bones, such as those of the feet, the Duska marker does not adequately focus attention on the critical area. This is primarily due to the size of the Duska marker; it is simply too large to place close to the cutaneous landmark without obscuring the subcutaneous problem. Finally, for fine work, such as in the examination of the small bones of the toes, it is useful to completely delineate the cutaneous area in question, preferably by encircling it rather than pointing at it.
A marker disclosed by Williams et al. (U.S. Pat. No. 4,860,331) comprises a tape with a plurality of index markings, wherein the tape is affixed to the patient's skin. The tape is a flexible one which cannot be accidently shifted or dislodged. The Williams marker provides an indexing means of identification for regions of the body which are subjected to scanning procedures such as computerized axial tomography. Rather than encompass small areas of interest, the Williams marker provides reference lines only. These lines may obscure rather than encompass an area of interest as small as individual bones of the toes. The Williams marker may be effective in indexing cross-sectional scans of the entire body, but it would hinder podiatric evaluations of much smaller areas of interest.
A further technique utilized to mark an area of interest is the three-dimensional marker disclosed by Gulleckson (U.S. Pat. No. 3,836,776). The three-dimensional marker has three elongated members disposed at right angles to each other and is normally embedded in a patient's wound in order to ensure proper positioning. The problem with this technique, in addition to its being painful, is that it is limited to pinpointing foreign objects in the body (somewhere in the vicinity of the wound) and therefore is generally not applicable to the examination of bones of the foot; among other disadvantages, the three-dimensional marker may actually obscure the area of interest.
A still further technique highlights the distinction between the needs of the various medical specialties when it comes to markers on x-ray films. An example of particular relevance to the present application is podiatry. Podiatrists are involved primarily in the evaluation of the small bones of the feet and are frequently concerned with isolating for examination very small subcutaneous areas based upon cutaneous landmarks which often exist on irregular surfaces in hard-to-reach locations. To overcome these particular problems, podiatrists commonly use a marking technique that involves forming a piece of wire into a loop, taping the loop around the area of interest and then taking the x-ray. One of the many drawbacks of this technique is that it takes the podiatrist a considerable amount of time to prepare the marker. Another problem is that the loops formed are often of nonuniform shape and size. The podiatrist may end up with a marker that encompasses the area of interest and is suitable for use with the small bones of the feet, but one which nevertheless results in considerable inconvenience to the podiatrist and which furthermore imposes on the podiatrist's time with his or her patient. An x-ray technique involving the use of a set of readily dispensable markers of various sizes and shapes which can encompass the area of interest would therefore increase the diagnostic efficiency and effectiveness of the podiatrist.
It is therefore an object of the present invention to overcome the problems associated with the prior art markers by providing to podiatrists a marker to be used in the evaluation of the small bones of the feet that will sharply delineate an area of interest without obscuring it.
It is another object of the present invention to provide to podiatrists markers of standard shapes and sizes which are readily accessible, easily dispensable, and which require no manipulation by the podiatrist at the point of deployment.